ELMEC 1110 Final Exam Review

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: What devices usually control the action of magnetic brakes?

• Solenoids

• Control relays

• Starting resistors

• Contactors

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: Most of the friction is produced in a magnetic brake as:

• Back-and-forth movement of the solenoid

• Magnetic field between the shaft and the friction disk

• Pressure between the shoes or pads and a disk mounted on the motor shaft

• Pressure applied directly by the solenoid on the motor shaft

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: What is the most common maintenance operation on friction brakes?

• Replacement of shoes or pads

• Replacement of the solenoid

• Adjustment of spring tension

• Adjustment of solenoid position

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: In jogging circuits, which device uses its power contacts prematurely due to rapid and repeated switching of inrush current?

• Push button

• Contactor

• Friction brake

• Selector switch

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: Which device is best suited to reduce stopping time during jogging?

• Control relay

• Inertia

• Selector switch

• Friction brake

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: Why are friction brakes used on electrical motors?

• Holding a motor position

• Quicker stops

• More precise stops

• All of the above

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: What is the effect of jogging on power contacts?

• It reduces their life expectancy

• It improves their conductivity

• It increases their life expectancy

• It has no particular effect

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: What is the alternate name for jogging?

• Starting

• Inching

• Running

• Maintaining

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: What is the main purpose of jogging?

• Reverse the motor rotation direction

• Accomplish large movements with a motor

• Accomplish small movements with a motor

• Start a motor continuously

Multiple Choice. Choose the one alternative that best completes the statement or answers the question: In most applications, the braking torque of friction brakes should be

• Equal or greater than full-load motor torque

• Equal or less than full-load motor torque

• Equal or greater than ten times the full-load motor torque

• Equal or less than ten times the full-load motor torque